Coating composition, heat-sensitive recording layer, heat-sensitive recording material, and corresponding uses and methods

Abstract

A coating composition for producing a heat-sensitive recording material and to a corresponding heat-sensitive recording layer. The coating composition includes one or more color developers, one or more dye precursors, one or more specific fatty acid amides, and one or more (additional) specific sensitizers. A heat-sensitive recording material including a carrier substrate and a heat-sensitive recording layer, to the use of specific fatty acid amides in order to increase the grease resistance of a heat-sensitive recording material or a heat-sensitive recording layer, and to a method for producing a heat-sensitive recording material or a heat-sensitive recording layer.

The invention claimed is: 
     
       1. A coating composition for producing a heat-sensitive recording material, comprising:
 at least one color developer, wherein at least one of the at least one color developer being a compound of formula (I) 
 
       
         
           
           
               
               
           
         
         wherein the compound of formula (I) is present in a crystalline form which in the IR spectrum has an absorption band at 3401±20 cm −1 , 
         at least one dye precursor; 
         at least one fatty acid amide each having a number of carbon atoms in a range from 16 to 24; 
         a sensitizer comprising at least one compound selected from the group consisting of 1,2-diphenoxyethane and ethylene glycol m-tolyl ether; and 
         a ratio of a total mass of fatty acid amides having a number of carbon atoms in a range from 16 to 24 to a total mass of compounds selected from the group consisting of 1,2-diphenoxyethane and ethylene glycol m-tolyl ether in the coating composition or the heat-sensitive recording layer being in a range from 4:1 to 1.2:1. 
       
     
     
       2. The coating composition as claimed in  claim 1 , further comprising at least one constituents from the group consisting of
 a further sensitizer, 
 a pigment, 
 a dispersant, 
 an antioxidant, 
 a release agent, 
 a defoamer, 
 a light stabilizer, and 
 a brightener. 
 
     
     
       3. The coating composition as claimed in  claim 2 , wherein:
 the at least one fatty acid amide have a number of carbon atoms in a range from 16 to 24 
 
       being octadecanamide and/or N-(hydroxymethyl)octadecanamide and/or
 possessing a melting point which is greater than 103° C. 
 
     
     
       4. The coating composition as claimed in  claim 3 , wherein
 a ratio of the mass of the compound of the formula (I) to a total mass of fatty acid amides having the number of carbon atoms in a range from 16 to 24 in the coating composition or the heat-sensitive recording layer being in a range from 1.2:1 to 4:1 
 and/or 
 a ratio of the mass of the compound of the formula (I) to the mass of octadecanamide and/or N-(hydroxymethyl)octadecanamide in the coating composition being in a range from 1.2:1 to 4:1. 
 
     
     
       5. The coating composition as claimed in  claim 1 , wherein a ratio of a total mass of fatty acid amides having a number of carbon atoms in the range from 16 to 24 to a total mass of compounds selected from the group consisting of 1,2-diphenoxyethane and ethylene glycol m-tolyl ether in the coating composition being in a range from 1.5:1 to 1.2:1. 
     
     
       6. The coating composition as claimed in  claim 1 , comprising as sensitizer 1,2-diphenoxyethane or a mixture of 1,2-diphenoxyethane and ethylene glycol m-tolyl ether. 
     
     
       7. The coating composition as claimed in  claim 1 , the at least one fatty acid amides having a number of carbon atoms in a range from 16 to 24 being octadecanamide and/or N-(hydroxymethyl)octadecanamide and/or possessing a melting point which is greater than 103° C. 
     
     
       8. A coating composition for producing a heat-sensitive recording material or heat-sensitive recording layer, comprising
 at least one color developer, wherein at least one of the at least one color developers being a compound of a formula (I) 
 
       
         
           
           
               
               
           
         
         wherein the compound of formula (I) is present in a crystalline form which in the IR spectrum has an absorption band at 3401±20 cm −1 , 
         at least one dye precursor; 
         octadecanamide and/or N-(hydroxymethyl)octadecanamide; 
         a sensitizer comprising, 1,2-diphenoxyethane and/or ethylene glycol m-tolyl ether, 
         wherein a ratio of a mass of the compound of the formula (I) to a mass of octadecanamide and/or N-(hydroxymethyl)octadecanamide in the coating composition being in a range from 1.2:1 to 4:1, 
         and 
         a ratio of a total mass of octadecanamide and N-(hydroxymethyl)octadecanamide to the total mass of 1,2-diphenoxyethane and ethylene glycol m-tolyl ether in the coating composition being in a range from 1.5:1 to 1.2:1. 
       
     
     
       9. A heat-sensitive recording material, comprising:
 a carrier substrate; and 
 a heat-sensitive recording layer comprising:
 at least one color developer, wherein at least one of the at least one color developer being a compound of formula (I) 
 
 
       
         
           
           
               
               
           
         
         wherein the compound of formula (I) is present in a crystalline form which in the IR spectrum has an absorption band at 3401±20 cm −1 ,
 at least one dye precursor; 
 at least one fatty acid a amide each having a number of carbon atoms in a range from 16 to 24; 
 a sensitizer comprising at least one compound selected from the group consisting of 1,2-diphenoxyethane and ethylene glycol m-tolyl ether; and 
 a ratio of a total mass of fatty acid amides having a number of carbon atoms in a range from 16 to 24 to a total mass of compounds selected from the group consisting of 1,2-diphenoxyethane and ethylene glycol m-tolyl ether in the coating composition or the heat-sensitive recording layer being in a range from 4:1 to 1.2:1. 
 
       
     
     
       10. The heat-sensitive recording material as claimed in  claim 9 , further comprising
 at least one interlayer disposed between the carrier substrate and the heat-sensitive recording layer 
 
       and/or
 wherein no further layer is disposed on a side of the heat-sensitive recording layer that faces away from the carrier substrate 
 and/or 
 wherein the carrier substrate consists of paper, synthetic paper, polymeric film, or an assembly of these materials. 
 
     
     
       11. A heat sensitive recording material comprising:
 a carrier substrate; and 
 a heat-sensitive recording layer, comprising: 
 at least one color developer, wherein at least one of the at least one color developer being a compound of formula (I) 
 
       
         
           
           
               
               
           
         
         wherein the compound of formula (I) is present in a crystalline form which in the IR spectrum has an absorption band at 3401±20 cm −1 , 
         at least one dye precursor; 
         at least one fatty acid amide each having a number of carbon atoms in a range from 16 to 24 and comprising octadecanamide and/or (N-hydroxymethyl)octadecanamide; 
         as a sensitizer, comprising at least one compound selected from the group consisting of 1,2-diphenoxyethane and ethylene glycol m-tolyl ether; and 
         a ratio of a total mass of fatty acid amides having a number of carbon atoms in a range from 16 to 24 to a total mass of compounds selected from the group consisting of 1,2-diphenoxyethane and ethylene glycol m-tolyl ether in the coating composition or the heat-sensitive recording layer being in a range from 4:1 to 1.2:1. 
       
     
     
       12. A method for producing a heat-sensitive recording material, comprising
 providing or producing a carrier substrate and also a coating composition comprising:
 at least one color developer, wherein at least one of the at least one color developers being a compound of formula (I) 
 
 
       
         
           
           
               
               
           
         
         wherein the compound of formula (I) is present in a crystalline form which in the IR spectrum has an absorption band at 3401±20 cm −1 ,
 at least one dye precursor; 
 at least one fatty acid amide each having a number of carbon atoms in a range from 16 to 24; 
 a sensitizer comprising at least one compound selected from the group consisting of 1,2-diphenoxyethane and ethylene glycol m-tolyl ether; and 
 a ratio of a total mass of fatty acid amides having a number of carbon atoms in a range from 16 to 24 to a total mass of compounds selected from the group consisting of 1,2-diphenoxyethane and ethylene glycol m-tolyl ether in the coating composition being in a range from 4:1 to 1.2:1; 
 
         applying the coating composition to the carrier substrate or an interlayer disposed thereon; 
         drying the applied coating composition, to give a heat-sensitive recording layer on the carrier substrate as the heat-sensitive recording material. 
       
     
     
       13. The method as claimed in  claim 12 , comprising:
 providing or producing the carrier substrate with the interlayer disposed thereon applying the coating composition to the interlayer; and 
 drying the applied coating composition, to give a heat-sensitive recording layer on the interlayer which is on the carrier substrate as the heat-sensitive recording material. 
 
     
     
       14. A method for producing a thermally printed heat-sensitive recording material, comprising:
 providing a heat-sensitive recording material comprising:
 a carrier substrate; and 
 a heat-sensitive recording layer comprising:
 at least one color developer, wherein at least one of the at least one color developer being a compound of formula (I) 
 
 
 
       
         
           
           
               
               
           
         
         
           wherein the compound of formula (I) is present in a crystalline form which in the IR spectrum has an absorption band at 3401±20 cm −1 ,
 at least one dye precursor; 
 at least one fatty acid amide each having a number of carbon atoms in a range from 16 to 24; 
 a sensitizer comprising at least one compound selected from the group consisting of 1,2-diphenoxyethane and ethylene glycol m-tolyl ether; and 
 
         
         a ratio of a total mass of fatty acid amides having a number of carbon atoms in a range from 16 to 24 to a total mass of compounds selected from the group consisting of 1,2-diphenoxyethane and ethylene glycol m-tolyl ether in the heat-sensitive recording layer being in a range from 4:1 to 1.2:1; and
 heat-treating the heat-sensitive recording material, so that the at least one color developer and the at least one dye precursor reacts so as to develop a coloration. 
 
       
     
     
       15. The method as claimed in  claim 14 , wherein the at least one fatty acid amide remains in the solid state at the location of the heat treating. 
     
     
       16. A heat-sensitive recording material, comprising a carrier substrate and a heat sensitive recording later formed from the coating composition in  claim 1 .